Plumbing a toilet on an uneven floor?

I'm rehabbing an old house and turning a small bedroom into a master bathroom and we're leaving the hardwood floor (don't ask!). The spot for the toilet is at the edge of the room where there is a significant amount of settling. From the left side of the toilet base to the right the floor drops about 3/4". So, the questions:

- should I mount the toilet flange flush to the floor or should I shim up the right side?

- if flush to the floor, then how do I make the toilet level? how do I make one side of the wax ring thicker than the other?

- besides fashioning a wood base to fit the underside of the toilet base is there any way to make this look normal? My carpentry skills are limited at best so I was hoping for a solution that didn't involve a band saw. Maybe shim up the right side and fill the space with fast setting joint compound? Will that fill 3/4"?

A 3/4" drop across the width of a toilet indicates a huge structural problem. I won't ask why you choose not to deal with it, but I can tell you that everything you have suggested would be look like hack job with doubtful success. You can put all the lipstick in the world on a pig, but when you're finished, it's still a pig. I realize this a very negative response to your question, but unless you deal with the cause of the problem, nothing is going to make this at all workable. Plumbers deal with slight variations in floors all of time with shims, but we're talking like 1/8" up to maybe 1/4". Leveling the floor is not a DIY job for a person with little or no carpentry skill and basic tools either.

From the left side of the toilet base to the right the floor drops about 3/4". So, the questions:

- should I mount the toilet flange flush to the floor or should I shim up the right side?

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The flange and toilet need to fit together properly, so the flange should be level with the toilet.

Do you have any idea why that floor is not flat and level? Unless I have misunderstood, it seems odd to me that a floor would be low next to a wall unless you have balloon framing and the joist next to the wall might be rotted or loose or something. There is always a way to make something work out, but first the actual problem must be known.

Thanks for the help guys. The house is brick and has settled towards the center of the house. The floor closest to the brick has settled the least. I always assumed this was because brick settles less than wood and the floor/beams/joists are attached to the brick so that part wouldn't settle near as much as the center of the house.

Maybe I'll remeasure. The dip in the floor is present on all 3 floors of the house and it really isn't noticeable unless you're looking for it.

You could have a sagging beam down the center of the house, or possibly a settled footer under a post. I once had a situation like that, and it was really not that big of a job to jack things back up from below and keep them where they should be.

The brick is resting on a concrete foundation and is not subject to settling. The sag in the center is due to failure of the interior supports. Can't be more specific than that with the information at hand. Up to you, but if it was mine I'd have a contractor examine the structure.

The width of the base of a Toto original Drake, for example, is 9" or .75 feet. A 3/4-inch slope across the base divided by .75 means a slope left to right of one-inch-per-foot. If the room is 15 feet wide, the drop from left to right would be fifteen inches, or a foot-and-a-quarter. That would be noticeable to the naked eye, I would think.

If the slope is more in the range of what Gary is talking about, then it's easy enough to shim the toilet. You don't need to money with the wax ring because you will get one that fills the gap on the long side and the other side will just smush around.

Thanks wjcandee for doing what we all should have done before spouting off with our wisdom. My God, if you had 15" drop across a room, get the heck out of the house, it's a goner! My old kitchen had a slope of about 1/2" across 15". It was livable, but when water was spilled, you know where it all went! This section of the house was moved from its original site and there was a high corner on the foundation. Fix it with new joist and flooring. Had to do some creative ceiling work too to get the cabinets to fit. Just the joys of trying to make an old piece of #### work like new.

OK, more info guys. Thanks for all the discussion about house leveling. The house is 30' deep and has 2 main beams running across the basement from one end to the other. Both of those beams have center support footers that have sunk about 1.5". The settling probably happened 100 years ago and hasn't changed since we moved in 8 years ago. At least I don't think it has! The beam didn't settle linearly, that is, the settling is most pronounced closest to the brick. It drops 1" in the first 5 feet and then another 1/2" in the next 10 feet to the center support.

Jacking up the house is a non-starter because the kitchen was built on the slanted floor. And I'm definitely not redoing the whole kitchen to accommodate a toilet upstairs!

I remeasured and the 3/4" drop is across the alcove that the toilet sits in which is 34" wide. The drop across the toilet base is more like 3/8". Given that is there anything I can use to fill a whole that big? Do they sell something thicker than caulk?

How deep is that alcove? I think I would be inclined to use something like a super-tough, "self-leveling" (still has to be troweled) thinset type of filler material a flooring company once sold me for making a wheelchair ramp where a bedroom floor was somehow about an inch above a bathroom floor even though the two floors met just fine at their corner of the hallway. I would cover the entire width of the alcove to make it level while feathering the area in front of the toilet on out to nothing at an angle across its width and into the room to ultimately make the entire thing "disappear" after new flooring has been applied.

I like the idea of pouring a base in the same shape as the toilet base. That way it will sit level and would be hardly noticeable! Would mortar be strong enough? I think it might be hard to pour concrete that's 1/2" on one side but almost 0 on the other.

I like the idea of pouring a base in the same shape as the toilet base. That way it will sit level and would be hardly noticeable! Would mortar be strong enough? I think it might be hard to pour concrete that's 1/2" on one side but almost 0 on the other.

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You could use self-leveling compound to pour a base that thin. There is the possibility that it would crack, but if you are pouring it in place it should be pretty solid. I don't know what you are dealing with, but I think it would be better to pour the entire bathroom floor.

I like the idea of pouring a base in the same shape as the toilet base. That way it will sit level and would be hardly noticeable! Would mortar be strong enough? I think it might be hard to pour concrete that's 1/2" on one side but almost 0 on the other.

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You need something other that a concrete product, including regular mortar, no matter what you do. Talk with a couple of floor specialists about the various compounds they have available, or even look for an industrial grout used for setting machinery. Also, and depending upon the actual structure of the toilet, it could be possible to flip it over and grind the entire bottom to a different plane that properly shortens the high side...but I really only mention that to illustrate your need to have a full-width horizontal floor or at least a toilet-sized spot on it to provide a solid place for the fixture to rest while you sit.

I have a floor where two pieces of tile spanned the toilet base and the two tiles were not level or even to each other. In my case it was not more then a 1/4 inch, maybe 3/16". I use those nylon shims that you can find in the plumbing parts section. After the install I then filled the gap with grout with enough pushed under the base where the grout would be a 1" or 2" under the base (to help support the weight). It also looks better than a big thick bead of caulking. The toilet flange should be set to the level of the highest part of the floor. With the other side of the toilet base shimmed up to level the of the flange you'll not have any leaks.

The toilet flange should be set to the level of the highest part of the floor.

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Actually, the flange should be mounted on top of the finished floor. (Maybe that's what you were saying, but it seemed like you were saying that the top of the flange should be level with the floor, which is not correct.)